1. Field of the Invention
The invention relates to Forearm and Wrist Supports and Rests for use with computer input devices, such as keyboards, xe2x80x9cmicexe2x80x9d, trackballs, graphics tablets, game controllers, joysticks, touch pads, and the like, and more particularly to such supports and devices designed to delay and/or prevent certain Repetitive Motion Disorders (RMD), Carpal Tunnel Syndrome, and general musculoskeletal fatigue.
2. Description Of Prior Art
It is recognized that extensive use of a manual computer input device such as a mouse, keyboard, etc. is fatiguing and stressful and in time can result in physical injury to the user""s wrist or forearm. It also is known that use of such input devices tends to produce general musculoskeletal fatigue which in turn can effect chronic injuries to areas of the body beyond those directly related to operation of the input devices, such as upper arm, shoulder, neck, and upper, and lower back injuries.
The existing medical and ergonometric literature and currently available remedies do not address the kinesiology of motion in the operation of computer input devices that apply musculoskeletal forces in multiple directions and often with the result of opposing physiological forces. Lifting the wrist, for example, causes contraction on the top of the wrist and elongation on the underside. The repetitive compound motions of the hand and wrist of a user of a computer input device causes musculoskeletal tensions. In the case of operating a computer mouse, for example, the index finger and associated muscles and tendons are holding the mouse button, while at the same time the hand, thumb, and other fingers are holding and causing the mouse to move. This latter motion also impacts the wrist and forearm that must twist on its axis to maintain pressure on the mouse and complete the desired action.
Common preventive measures and recommendations for minimizing or preventing RMD injuries, and/or for providing relief or care of such disorders, are frequent breaks during the work day, changes in body position, frequent massaging of body parts, and specific exercise before returning to work with input devices.
A number of patented wrist or arm supports are known which address the problems of RMD, Carpal Tunnel Syndrome, and general musculoskeletal fatigue. Such supports have either provided a static surface upon which the user is able to support the wrist or forearm while typing or operating a mouse or another type of input device, or have provided a static support functionality while also providing for motion in a linear fashion across the support by the use of one or more rollers or beads mounted for single-direction, i.e., single axis, rotation. Wrist or forearm rests that provide a static support surface tend to reduce the extent of musculoskeletal stress and fatigue resulting from holding the hand, wrist, and forearm aloft while entering data or operating an input device. Those support devices comprising rollers or beads mounted for rotation on a single axis are somewhat better at reducing stress and fatigue with respect to movement of the user""s hand and arm forward and backward over a keyboard or in the operation of a computer mouse or other input device.
U.S. Pat. No. 5,971,331 issued Jun. 19, 1997 to James G. Getsay, discloses a stationary device for supporting a wrist or hand of a person during use of a computer keyboard and mouse which utilizes angularly positioned rollers for providing maximum contact points and comfort for support of the user""s wrist and/or hand. U.S. Pat. No. 5,467,950, issued Feb. 9, 1993 to D. Dumitru, discloses a stationary forearm/wrist support that includes a plurality of beads rotatable about a fixed rod. U.S. Pat. No. 5,050,826, issued Sep. 24, 1991 to K. M. Johnston, shows a stationary hand/wrist support comprising padded rollers mounted adjacent to a keyboard. A similar arrangement is disclosed by U.S. Pat. No. 5,478,034, issued Dec. 26, 1995 to E. E. Cunningham et al. U.S. Pat. No. 5,386,956, issued Feb. 7, 1995 to D. M. Hatcher, shows a stationary wrist support device for persons using a keyboard that is tiltable to adjust the support angle.
The devices disclosed in the foregoing patents, which are representative of what has been available prior to this invention, have a common limitationxe2x80x94although they provide wrist or forearm support, they facilitate freedom of motion in a single direction. In the conception of this invention, it has been recognized that a satisfactory device should not only support the hand, wrist, and/or forearm of a person using a computer input device of the type described, but in addition the supporting means should be capable of motion in multiple directions so as to allow a compound range of motions of the supported hand, wrist or forearm with negligible negative force applied against the motions.
Accordingly the primary object of this invention is provide a support device for users of computer input devices, or other input devices involving intensive hand and wrist motion activity, that comprises supporting means capable of multi-directional rotation so as to provide support through a compound range of hand/wrist motions, with little or no negative force to prevent or substantially impede such motions.
Another object of the invention is to provide a novel support for an operator""s hand, wrist and/or forearm that a provides a massaging action as the supported member undergoes motion in various directions.
A further object is to provide a multi-directional hand, wrist, and/or forearm support for computer operators and the like which can be easily and economically manufactured using a variety of materials.
Another object is to provide an ergonomically designed device for supporting the hand, wrist, and/or forearm that provides a supporting and massaging action for the supported appendage continuously through a compound range of motions.
Still another object is to provide an appendage support that can be made in different sizes according to the input device with which it is intended to be used.
Another more specific object is to provide a device that facilitates multi-directional movement of a supported hand, wrist, or forearm of a person, thereby aiding the person to reach and operate a keyboard, computer mouse, trackball, game controller or other hand operated input device.
These and other objects are achieved by providing a device that comprises a plurality of spherical balls, and a housing or cage having means for rotatably captivating the spherical balls in side-by-side relation and in position to function as a support for a wrist or forearm that extends over the device, the spherical balls being rotatable in response to movement of the supported wrist or forearm so as to facilitate multi-directional motion of the supported appendage. Each ball is captivated against vertical movement relative to the housing and also is in contact with neighboring balls or a neighboring ball and a side wall of the housing or cage. In the preferred embodiment of the invention, each ball makes a three-point contact with the housing or cage in a vertical plane, thereby minimizing resistance to rotation induced by the weight of the supported appendage on the balls. As the user""s wrist or forearm twists and moves back and forth in the action of clicking and moving a computer mouse, for example, the spherical balls (a) support the wrist or forearm and (b) simultaneously rotate under the influence of the supported wrist or forearm as the latter undergoes multi-directional movement over the device. In addition to their support function, the spherical balls serve as a musculoskeletal massaging tool to help reduce stress and fatigue.